A touch panel is used in a state of being stacked on a display device. Therefore, sensor electrodes formed in a display area are usually formed with transparent conductive films made of indium tin oxide (ITO), indium zinc oxide (IZO), or the like.
On the other hand, in a frame region other than the display area, metal wiring having a low electric resistance is used in some cases. The metal wiring, however, corrodes when being exposed to atmosphere or moisture. Therefore, if metal wiring is exposed, long term reliability is poor in some cases.
JP2004-61687A discloses a substrate for a liquid crystal display device, the substrate including a plurality of bus lines, an insulating resin layer formed on the bus lines, pixel electrodes formed on the insulating resin layer, thin film transistors connected to the pixel electrodes and the bus lines, and external connection terminals electrically connecting external circuits and the bus lines.
This substrate for a liquid crystal display device includes a first terminal electrode electrically connected to a bus line, a structure that is formed on at least a part of an area on a periphery of the first terminal electrode, a second terminal electrode formed on the first terminal electrode and the structure, and an electrode reconnection area for reconnecting the first and second terminal electrodes. Here, the structure is made of a forming material different from that of the insulating resin layer, and the second terminal electrode is made of the same forming material as that of the pixel electrode.
The above-described document discusses that as the structure is made of a forming material different from that of the insulating resin layer, the second terminal electrode and the structure can be formed in a close contact state.